“Effective topical sinus delivery and therapy is a product both of delivery device and surgical state,” he said. “The surgical state is critical—we have to get that right.”
Explore This IssueOctober 2012
Stents and Carriers
Rodney Schlosser, MD, professor of otolaryngology at the Medical University of South Carolina in Charleston, who talked about new agents and delivery techniques, said there is limited early evidence for non-biodegradable drug-eluting stents and they deliver just 0.3 mL over a month’s time. “It’s such a small amount, you wonder about the efficacy; appropriate studies are needed,” he said.
Concerns about bioresorbable stents and carriers include their potential to inhibit mucociliary clearance while in place and unknowns such as replacement frequency and the potential to become infected if kept in place for prolonged periods. Additionally, while the description makes it sound as though they just evaporate, they’re actually degraded by inciting a local inflammatory response that dismantles them, similar to an absorbable suture, Dr. Schlosser said.
Trials have found improvements with steroid-containing bioresorbable stents over stents alone, but Dr. Schlosser said that while early reports are promising and the level of evidence for some devices is getting stronger, caution should be exercised when interpreting such results until steroid-containing bioresorbable stents can be compared with controls in whom nothing was placed.
“The other question is, even if this works, what about the cost and duration of effect?” he said. “Those are questions [to which] we still don’t know [answers].”
Liposomes, bubbles made of a bilayer of lipids that can be integrated into the cell membrane, thereby delivering drugs intercellularly, are another option being investigated. The drug-delivering “nanoparticle” that uses antibodies for targeting is another possible vehicle that is emerging, although they also come with the potential for an immunogenic or pro-inflammatory response, Dr. Schlosser said.
Newer active agents under study range from immunomodulatory agents to antioxidants to gene therapy. He added that complement inhibition is another promising area. A C3a receptor blocker has been found to protect against development of CRS. It has potential as a topical therapy, he said, even though researchers don’t yet have a complete understanding of how it works.
P.J. Wormald, MD, professor and chair of the department of otolaryngology-head and neck surgery at the University of Adelaide in Australia, talked about the importance of limiting the formation of biofilm in chronic rhinosinusitis, which can inhibit treatment and causes worse long-term outcomes. Nitric oxide might be one tool for accomplishing this goal. Studies at his center have found dose-dependent effects of nitric oxide in decreasing the amount of S. aureus biofilm.